Owners and operators of petroleum underground storage tank systems must provide release detection for tanks and piping as follows:

1. 1. Tanks. Tanks must be monitored for releases as follows:

1. a. Tanks installed on or before September 28, 2018, must be monitored for releases at least every thirty days using one of the methods listed in subsections 4 through 9 of section 33.1-24-08-33 except that: 1. (1) Underground storage tank systems that meet the performance standards in section 33.1-24-08-10 or 33.1-24-08-11, and the monthly inventory control requirements in subsection 1 or 2 of section 33.1-24-08-33, may use tank tightness testing (conducted in accordance with subsection 3 of section 33.1-24-08-33) at least every five years until ten years after the tank was installed and tanks with capacity of five hundred fifty gallons [2081.98 liters] or less and tanks with a capacity of five hundred fifty-one to one thousand gallons which meet the tank diameter criteria in subsection 2 of section 33.1-24-08-33 may use manual tank gauging (conducted in accordance with subsection 2 of section 33.1-24-08-33). 2. (2) Tanks installed after September 28, 2018, must be monitored for releases at least every thirty days in accordance with subsection 7 of section 33.1-24-08-33.

2. 2. Piping. Underground piping that routinely contains regulated substances must be monitored for releases in a manner that meets one of the following requirements:

1. a. Piping installed on or before September 28, 2018, must meet one of the following: 1. (1) Pressurized piping. Underground piping that conveys regulated substances under pressure must: 1. (a) Be equipped with an automatic line leak detector conducted in accordance with subsection 1 of section 33.1-24-08-34; and 2. (b) Have an annual line tightness test conducted in accordance with subsection 2 of section 33.1-24-08-34 or have monthly monitoring conducted in accordance with subsection 3 of section 33.1-24-08-34. 2. (2) Suction piping. Underground piping that conveys regulated substances under suction must either have a line tightness test conducted at least every three years and in accordance with subsection 2 of section 33.1-24-08-34, or use a monthly monitoring method conducted in accordance with subsection 3 of section